Plants are periodically evaluated in-field to estimate their size, stage of growth, sufficiency of watering, size of the fruit, presence/absence of pests or disease, or other observable traits or characteristics. Such evaluation of the plants is referred to as phenotyping.
FIG. 1A is a picture of plants obtained in accordance with conventional technology. With some conventional technologies, the in-field phenotyping involves acquiring optical images of the plants. These images are subsequently analyzed to establish relevant properties of the plants, for example, size of the plant, size of the fruit, etc. In many applications, the subsequent treatments of the plants (e.g., watering, application of pesticides, harvesting, etc.) is decided based on the analysis of the images. However, conventional imaging generates a large volume of relatively incomplete or difficult-to-analyze data. For example, the parts of plants may be occluded or obscured such that the relevant plant properties are difficult to derive from the images. Therefore, trained operators sometimes physically separate (physically “segment”) a plant 10 from the rest of the plants to make the outline of the plant 10 sharper and, thus, more suitable for the subsequent analysis of the acquired image. However, such an individualized treatment of the target plants increases the cost and time of the in-field phenotyping.
FIG. 1B is a picture of the plant 10 obtained in accordance with conventional technology. With the illustrated conventional technology, a physical backdrop 12 is placed behind the plant 10 to improve the isolation/contrast of the plant 10 against other plants in the field, therefore improving the sharpness of the image. As a result, the analysis of the image of the plant 10 is more accurate. However, the placement of the physical backdrops increases the time required for acquiring images and the cost of the phenotyping.
FIG. 1C is a graph of plant phenotyping results obtained with conventional technology. With some conventional technologies, the internal or otherwise occluded plant features can be exposed by the operators prior to imaging these plant features. For example, the operator may remove the husk that hides the corn ear structure prior to imaging corn kernels 14. Once a relatively sharp outline of the corn kernels 14 is imaged, the size of the corn kernels may be obtained by fitting a suitable periodic curve 16 having amplitude and period that approximates the size of the corn kernels. Next, the curves 16 can be represented as a frequency-amplitude graph 17. In the illustrated example, one or more peaks in the graph 17 correspond to the dominant or the average length of the corn kernels 14. However, this conventional technology results in a physical destruction of the corn ear structure that is evaluated.
Accordingly, there remains a need for in-field plant phenotyping techniques and system having a high-throughput and low cost of acquiring the images that can be analyzed to produce accurate data about the plants under review.